From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 798C7C6FA8B for ; Mon, 19 Sep 2022 12:42:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230022AbiISMmy (ORCPT ); Mon, 19 Sep 2022 08:42:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230011AbiISMmx (ORCPT ); Mon, 19 Sep 2022 08:42:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1499B38A7; Mon, 19 Sep 2022 05:42:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A5D8161BBC; Mon, 19 Sep 2022 12:42:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B63C5C433C1; Mon, 19 Sep 2022 12:42:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663591366; bh=5YMfYGPidhjUcu5gKVhMTnepXT5HmE6p4KDzCeRUFzc=; h=Subject:From:In-Reply-To:References:To:Cc:Date:From; b=qb2QCvRHFqWNN+1oerIA2AFGZicYV/jrd9RehDCxkmboD0qukgWcdTcS0BwIDsoxP W1qPA+EIVMs/TIs9uhfvjaXxb5ty/zWhAQt9tk2hrYr3926d84ztm9ksl+rAQSXrun AMMgix7f4z5etC2mdp2iWZ2fbLHbcvyeAEx3fiVqHF2WdTzyJ2w8yN/vQdev2gmlnU PassOVv7+NysUGgIK7qhonfZMIk/IyH81RT3dLIRk7+e1hn3bzaZBAXdagAVME82ye ZrGpQSUBdkP0dHxUW6QTGYTHxOIae2Be9djHlVPi1MRKNByIU4Ya4jgkCAonJ9hZbf nC8lZt76mJGUQ== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [PATCH v3 1/1] wcn36xx: Add RX frame SNR as a source of system entropy From: Kalle Valo In-Reply-To: <20220915004117.1562703-2-bryan.odonoghue@linaro.org> References: <20220915004117.1562703-2-bryan.odonoghue@linaro.org> To: Bryan O'Donoghue Cc: loic.poulain@linaro.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, wcn36xx@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, bryan.odonoghue@linaro.org, "Jason A . Donenfeld" User-Agent: pwcli/0.1.1-git (https://github.com/kvalo/pwcli/) Python/3.7.3 Message-ID: <166359136168.17652.16916114902781460375.kvalo@kernel.org> Date: Mon, 19 Sep 2022 12:42:43 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Bryan O'Donoghue wrote: > The signal-to-noise-ratio SNR is returned by the wcn36xx firmware for each > received frame. SNR represents all of the unwanted interference signal > after filtering out the fundamental frequency and harmonics of the > frequency. > > Noise can come from various electromagnetic sources, from temperature > affecting the performance hardware components or quantization effects > converting from analog to digital domains. > > The SNR value returned by the WiFi firmware then is a good source of > entropy. > > Other WiFi drivers offer up the noise component of the FFT as an entropy > source for the random pool e.g. > > commit 2aa56cca3571 ("ath9k: Mix the received FFT bins to the random pool") > > I attended Jason's talk on sources of randomness at Plumbers and it > occurred to me that SNR is a reasonable candidate to add. > > Cc: Jason A. Donenfeld > Signed-off-by: Bryan O'Donoghue > Signed-off-by: Kalle Valo Patch applied to ath-next branch of ath.git, thanks. e1a6b5d3a971 wifi: wcn36xx: Add RX frame SNR as a source of system entropy -- https://patchwork.kernel.org/project/linux-wireless/patch/20220915004117.1562703-2-bryan.odonoghue@linaro.org/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches